JP2002280703A - Electronic component mounting board and mounting method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mounting substrate and a mounting method using the same, in which alignment is easy and connection reliability is high even when there is a variation in bump height. The purpose is to provide. An electronic component including a semiconductor element is provided.
Board 20 having concave portion 24 capable of receiving conductive portion 11 at a position corresponding to conductive portion 11 of electronic component 10 having conductive portion 11 having a convex shape, and mounting method using the same It is.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for mounting semiconductor elements, electronic components and the like having excellent connection reliability and a mounting method using the same.

[0002]

2. Description of the Related Art In recent years, with the development of electronic equipment, the mounting density of electronic components has increased, and semiconductor packages having a size substantially equivalent to a semiconductor chip size called a chip scale package or a chip size package or a bare chip mounting of semiconductors have been developed. A new type of mounting method has begun to be adopted.

One of the most important characteristics of a mounting board on which various electronic components such as semiconductor elements are mounted is connection reliability. It is necessary to accurately align and connect the connection portions between various electronic components such as semiconductor elements and the mounting board. However, miniaturization has progressed and accurate alignment has become difficult. When misalignment occurs, not only initial connection failures occur, but also connection reliability against thermal fatigue may decrease, so accurate alignment is directly related to the reliability of equipment using mounting boards. This is an important item.

In bare chip mounting, there is a method of connecting electrodes of a semiconductor chip to wiring pads of a wiring board using solder balls. According to this method, when the solder is melted, the solder is aligned by a self-alignment effect.
The effect can be expected. However, the use of solder is not preferable in terms of environmental measures because it contains lead. In a method in which small projections called bumps are formed on the chip side and connected with a conductive paste or the like, the above-described self-alignment effect is not provided, so that alignment is difficult. There is also a method of connecting the electrodes of the semiconductor chip and the wiring pads of the wiring board using conventional bonding wires.However, in order to protect the bonding wires, a sealing material resin must be coated, and the number of mounting steps is increasing. Was. For this reason, there is a demand for a mounting method which is highly reliable, can perform electrical connection and chip fixing in a batch, and does not have a material such as lead which is harmful to the environment.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a mounting board and a mounting method using the same, which are easy to align and have high connection reliability even when the height of bumps varies. With the goal.

[0006]

That is, the present invention is directed to a mounting board for an electronic component including a semiconductor element, the electronic component having a conductive portion having a convex shape, the electronic component being provided at a position corresponding to the conductive portion. A substrate having a recess capable of receiving a conductive portion and a mounting method using the substrate.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an electronic component such as a semiconductor element receives a conductive portion having a convex shape of the electronic component in a concave portion provided on the mounting substrate and corresponding to the conductive portion. By doing so, the alignment is performed.

Here, it is preferable that, after arranging the conductive portion of the electronic component and the concave portion provided on the mounting substrate in correspondence with each other, one of them is subjected to vibration, ultrasonic wave, compressive stress or the like. This is because the convex conductive portions can be stably accommodated in the corresponding concave portions of the mounting substrate.

The conductive portion having a convex shape may be a known one such as a printed bump made of silver paste or the like.
For example, a plated bump, a gold wire bonded to the conductive portion, cut and formed into a ball shape may be used.
As the forming method, known methods, for example, metal plating, formation of gold bumps using an improved wire bonder, printing of conductive resin or insulating resin, molding of means such as single use or combination as necessary do it. Above all, it is possible to form using a conductive paste, it flows at the time of curing after completion of alignment, and due to surface tension,
The so-called self-alignment effect is preferable in that not only the reliability of the connection is improved because the alignment can be performed more accurately, but also the connection resistance between the mounting substrate and electronic components such as a semiconductor chip is reduced.

On the other hand, the form of the concave portion provided on the mounting substrate side may be any shape as long as the conductive portion can be received, and for example, a hole (not necessarily penetrating the mounting substrate). It is not necessary to be a hole, and it may be adjusted according to the mode of the circuit to be connected to the conductive portion, and typical ones are illustrated in FIGS.
Is a depression, (b) is a through hole, and (c) is an IVH / interfacial via hole. Note that FIG. 1 is a cross-sectional view, but the drawing is complicated, so that diagonal lines are not shown except for the “circuit” and some members), and a bank built around the circuit with an insulating resin such as a resist ( 1 (d) and 1 (e)), a film-like insulating resin having a through hole formed at a predetermined position is attached to the upper surface of a mounting substrate (FIG. 1).
(See FIG. 1 (f)), and those provided with depressions corresponding to a plurality of conductive portions (see FIG. 1 (g)). In FIG. 1, reference numeral 10 denotes an electronic component such as a semiconductor chip, 11 denotes a bump as a conductive portion, 20 denotes a mounting board, 21 denotes a circuit provided on the mounting board, 22 denotes an insulating resin such as a resist, and 23 denotes a film. The insulating resin 24 is a concave portion. As a method of forming the concave portion, a known method, for example, a method of molding with a mold, a method of punching and etching with a laser or a drill, a method of applying, exposing, and developing a resist can be used. Further, the IVH for interlayer connection may be used as a concave portion as it is.

Further, an adhesive or an adhesive film may be interposed and pressed between the mounting substrate and an electronic component such as a semiconductor chip. This is because the mounting substrate and the electronic component are firmly adhered to each other, so that the electronic component is less likely to be separated, and the reliability is further improved.

In the present invention, the height of the conductive portion having a convex shape is preferably not less than 1 and not more than 10 times the depth of the concave portion of the mounting board. If the ratio is less than 1, the connection reliability may not be ensured. On the other hand, if the ratio is more than 10, the protruding portions are unnecessarily long, which is disadvantageous in terms of cost. This is because there is a possibility that it is disadvantageous in terms of handling, workability and the like.

The maximum diameter of the conductive portion having a convex shape is preferably 0.5 times or more and 10 times or less the diameter of the concave portion of the mounting board from the viewpoint of preventing connection failure after processing (FIG. In the embodiment of (g), the cross-sectional distance between the outermost conductive portions and the cross-sectional distance of the outermost circuit are respectively read.
If the ratio is less than 0.5, the possibility of disconnection increases, and if it exceeds 10 times, the possibility of short-circuit increases, although it depends on the material forming the conductive portion having a convex shape.

In the present invention, the adhesive and the adhesive film include an insulating adhesive, an insulating film, an anisotropic conductive adhesive having conductive particles in the insulating adhesive, and an anisotropic conductive adhesive having conductive particles in the insulating film. A film or the like can be used.

These materials include, but are not limited to, resins such as epoxy resins, cyanate ester resins, cyanate resins and silicone resins, and high molecular weight components such as acrylic rubber and acrylonitrile butadiene rubber. Epoxy resins are particularly preferred in that they have good heat resistance after curing. The use of an adhesive or an adhesive film is preferable in that electrical connection and fixing of electronic components such as semiconductor chips can be performed at the same time.

[0016]

EXAMPLE 1 A terminal part of a semiconductor chip (10 mm square, using a logic element having a thickness of 450 μm) was coated with a conductive paste (Silver paste manufactured by Hitachi Chemical: EN-4700A) at a height of 20 μm and a maximum diameter of 30 μm. Bump (1 inward from the outer edge of the chip)
mm, 38 lines were formed at 1 mm intervals linearly. On the other hand, concave portions (number: 38) having a depth of 10 μm and a maximum diameter of 50 μm were formed in a pad portion of a wiring board obtained by circuit-working a copper-clad laminate using a mold. After positioning them with a maximum error of 20 μm using a semiconductor mounting device (CM-110 manufactured by Hitachi Tokyo Electronics), 16
On a hot plate at 0 ° C., a load of 1 kg was applied for 3 seconds to flow and harden the conductive paste. After curing at 170 ° C. for 1 hour, the space between the semiconductor chip and the wiring board is sealed with a resin (Hitachi Chemical's sealing material: CEL-C-7200).
For 1 hour.

Example 2 A bump having a height of 10 μm and a maximum diameter of 40 μm was formed by copper and gold plating, and the size of the formed recess was 5 depth.
μm, maximum diameter: 50 μm, a B-stage adhesive film (HS-231S manufactured by Hitachi Chemical Co., Ltd.) having a thickness: 25 μm between the semiconductor chip and the mounting board, and a temperature of the hot plate of 160 μm. A wiring board on which a semiconductor chip was mounted was prepared in the same manner as in Example 1 except that the temperature was changed to ° C.

Comparative Example 1 A wiring board on which a semiconductor chip was mounted was prepared in the same manner as in Example 1 except that no recess was formed in the wiring board.

Comparative Example 2 A wiring board having a semiconductor chip mounted thereon was produced in the same manner as in Example 2 except that no recess was formed in the wiring board.

Evaluation method The sample was left in an atmosphere of -55 ° C for 30 minutes, and then
The process of leaving the substrate in an atmosphere of 25 ° C. for 30 minutes is one cycle, and after 300 cycles, 500 cycles, and 1000 cycles.
After cycling and after 2,000 cycles, using an ultrasonic microscope, "○" indicates that no peeling or cracking of the joint with the semiconductor chip occurred, and "X" indicates that occurred, indicating "reliability". Was evaluated. After the semiconductor chip was mounted on the wiring board, the cross section was observed with a scanning electron microscope, and the amount of displacement between the center of the semiconductor chip and the center of the wiring board was measured. Tables 1 and 2 show the results.

[0021]

[Table 1]

[0022]

[Table 2]

The connection reliability was high in the case where the concave portion was formed in the pad portion of the wiring board as in the example.

[0024]

As described above, according to the mounting board of the present invention and the mounting method using the same, alignment is easy,
Moreover, a connection with excellent reliability can be obtained. If an adhesive film is used, the electrical connection between the electronic component and the mounting substrate and the fixing of the semiconductor chip can be performed simultaneously, so that the productivity is further improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a concave portion of the present invention together with an electronic component.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Electronic component (semiconductor chip) 11 Conductive part (bump) 20 Mounting board 21 Circuit 22 Insulating resin 23 Film-shaped resin 24 Concave part (pad part)

Continued on the front page F term (reference) 5E319 AA03 AB05 AC01 AC16 BB04 CC12 CC61 CD04 CD26 GG09 GG15 GG20 5E336 AA04 BC25 CC32 CC44 CC55 EE05 EE07 EE08 GG09 GG14 5E338 BB04 BB13 BB19 BB75 EE31 KK02 KK02 KK

Claims (6)

[Claims] An electronic component having a conductive portion having a convex shape has a concave portion capable of receiving the conductive portion. 2. The height and the maximum diameter of the conductive portion are 0.1-1 and 0.1-0.1, respectively.
2. The mounting board according to claim 1, wherein the mounting board is 2. 3. An electronic component having a concave portion capable of receiving a conductive portion of an electronic component having a conductive portion having a convex shape, and positioning the conductive portion and the concave portion by matching the conductive portion with the concave portion. Component mounting method. 4. The mounting method according to claim 3, wherein after the positioning, a vibration, an ultrasonic wave, or a compressive stress is applied to the mounting substrate. 5. The mounting method according to claim 3, wherein an adhesive or an adhesive film is interposed between the electronic component and the mounting board. 6. The method according to claim 3, wherein the conductive portion is caused to flow into the concave portion after the alignment is completed, and is bonded.
6. The mounting method according to any one of items 1 to 5.